AB0572 DIFFERENTIAL BACKGROUND OF CLINICAL AND IMMUNOHISTOLOGICAL CHARACTRSITICS IN SYSTEMIC LUPUS ERYTHEMATOSUS AND RHEUMATOID ARTHRITIS COMPLICATED WITH HEART DISEASE
Authors: T. Kawamoto, H. Amano, S. Matsushita, K. Minowa, M. Matsushita, K. Yamaji, A. Amano, N. Tamura
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) are often complicated by heart disease. In severe cases, heart surgery is required, but little is known about clinical background and immunohistological pathology of diseases. <h3>Objectives</h3> The differences in clinical and immunohistological backgrounds of each disease were examined by comparing cases of heart disease associated with SLE and RA. <h3>Methods</h3> From 2012 to 2021, we observed 45 patients with SLE (32 patients underwent surgery), 67 patients with RA (33 patients underwent surgery), and 8 patients with overlapping SLE/RA (3 patients underwent surgery), all complicated with heart disease. The heart disease cases were divided into the aortic valve disease (Av), mitral valve disease (Mv), ischemic heart disease (I), and aortic aneurysm disease (Aa) groups, all from patients who had visited our hospital. The SLE (S) group consisted of Av, Mv, I, and Aa in 5, 6, 11, and 13 respective cases (10 duplicate cases), and in the RA (R) group there were 24, 12, 15, and 10 respective cases (6 duplicate cases). Immunohistological analysis of patients with left atrial appendage tissue (seven SLE, six RA, and two overlapping SLE/RA patients) was performed on left atrial cardiomyocytes for anti-human IgG, IgM, and C3 antibodies. Left atrial cardiomyocytes of eight cases of heart disease with non-connective tissue disease were used as the control. <h3>Results</h3> The age (in years) at diagnosis of heart disease in the S and R groups was S/R: 57.6/71.5 (p=0.057), and the duration (in years) from onset of the connective tissue disease to onset of the heart disease was S/R: 22.6/10.1 (p&lt;0.001). Anti-SS-A antibody (P=0.041), anti-U1RNP antibody (p=0.0044), and anti-CLβ2GP1 antibody (p=0.022) showed a high positivity rate in the S group. In disease I, the age at the time of diagnosis of heart disease was S/R: 51.6/70.9 years (p = 0.0083); and in disease Aa, the age and duration of disease were S/R: 63.5/74.8 years (p = 0.0088) and 29.6/7.0 years (p = 0.0013), respectively. There was no significant difference in S/R in patients suffering from diabetes, hypertension, and hyperlipidemia. Immunohistological analysis revealed IgG deposition in the cardiomyocytes in six of the seven patients in the S-alone group, while no IgG deposition was observed in six patients in the R-alone group. In two patients with overlapping S-R, IgG deposition was observed in both. In the S group, two or more antibodies of antiphospholipid antibodies, anti-Ro/SSA or anti-U1RNP antibodies, were positive in five out of the seven patients, and preoperative anti-DNA antibody elevation or complement reduction was seen in only two patients. Two of the seven patients in the S group were negative for either antibody, and a patient showed no IgG deposition uniquely in the S group. Both patients with overlapping S-R were positive for anti-CL antibody and anti-Ro/SSA antibody. In the R group, all antibodies were negative within the measured range. <h3>Conclusion</h3> A comparison of SLE and RA patients complicated with heart disease revealed that the SLE patients tend to be younger at diagnosis than RA patients and had a longer morbidity period. It is possible that various autoantibodies, such as antiphospholipid antibodies, anti-Ro/SSA antibodies, and anti-U1RNP antibodies were involved and had immunological effects on the myocardial tissue. In contrast, in RA patients complicated with heart disease, the autoantibodies observed in SLE were negative, and immunoglobulins were not deposited in the myocardial tissue of the RA patients who underwent surgery, suggesting that immunological involvement was poor and older diagnostic age was involved. <h3>References</h3> [1]Ju Zhang, Jie Gao, Ruina Kong, et al. Clinical Rheumatology 2022; 41(2):377-386 [2]Sara R, Schoenfeld, Shanthini Kasturi, et al. Seminars in Arthritis and Rheumatism 2013; 43: 77-95 <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.